• Korean Journal of Microbiology
• /
• v.31 no.1
• /
• pp.48-53
• /
• 1993

For the purpose to improve the glucoamylase productivity of Saccharomyces diastaticus, we integrated STA 1 gene into chromosomal DNA of S. diastaticus using YIp vector. After construction of Ylp-STA by the subcloning of STAI (5.3 kb) into YIp5 vector, S. diastaticus GMT-II(a. ura3. STAJ) was transformed by Ylp-STA through homologous recombination at the chromosomal STAJ gene. So we obtained the tram formants that glucoamylase productivity was increased maximum six fold. These strains transformed by the multi-copy integration of Ylp-STA in chromosomal DNA were confirmed by Southern hybridization. And the integrated Ylp-STA was maintained stably during 30 mitotic divisions.

• Microbiology and Biotechnology Letters
• /
• v.14 no.4
• /
• pp.311-318
• /
• 1986

Glucoamylase and ethanol productivities of HSDD-170 and HSDM-119 formed by S. cerevisiae and S. diastaticus protoplast fusion were investigated. For the production of the glucoamylase, soluble starch as carbon source, yeast extract and C. S. L as nitrogen source added into the basal medium were favorable. The production of the enzyme reached at maximum after cultivation of the fusant for 4 days at 3$0^{\circ}C$, aerobically. The properties of glucoamylase produced by fusants were very similar to those produced by S. diastaticus as based on optimum temperature, pH stability. In alcohol fermentation from starch, strain HSDD-170 fermented starch faster than either of its parental strains. The maximum of alcohol yield in 15% of liquefied potato starch was 7.5% (v/v).

• Journal of Microbiology
• /
• v.37 no.1
• /
• pp.35-40
• /
• 1999

Sporulation-specific glucoamylase (SGA) gene was isolated from genomic library of Saccharomyces diastaticus 5114-9A by using glucoamylase non-producing mutant of S. diastaticus as a recipient. When the glucoamylase activities of culture supernatant, periplasmic, and intracellular fraction of cells transformed with hybrid plasmid containing SGA gene were measured, the highest activity was detected in culture supernatant. SGA produced by transformant and extracellular glucoamylase produced by S. diastaticus 5114-9A differed in enzyme characteristics such as optimum temperature, thermostability, and resistance to SDS and urea. But the characteristics of SGA produced by sporulating yeast cells and vegetatively growing transformants were identical.

• Microbiology and Biotechnology Letters
• /
• v.17 no.6
• /
• pp.606-610
• /
• 1989

For the purpose of improving glucoamylase productivity of Saccharomyces diastaticus, useful yeast in direct ethanol fermentation of starch, the effects of growth rate on the plasmid stability and glucoamylase productivity of S. diastaticus harboring recombinant plasmid pYES 18 containing glucoamylase gene STA 1 were investigated. In a selective medium, the recombinant plasmids were maintained stably at constant level but glucoamylase productivity was very low. On the other hand, in the complex medium containing starch, growth rate of the cell was stimulated by the supplementation of glucose and plasmid stability was improved by growth stimulation. We can conclude that glucoamylase productivity of S. diastaticus harboring the recombinant plasmid was increased as the maintaining of high plasmid stability in the cell.

• Microbiology and Biotechnology Letters
• /
• v.14 no.4
• /
• pp.305-310
• /
• 1986

To improve the starch fermentation ability of yeast, hybrids were introduced by protoplast fusion of S. cerevisiae and S. diastaticus. The protoplasts of parental auxotrophic cells were fused in the presence of 10 mM CaCl$_2$and 30% of polyethyleneglycol (M.W 4, 000). The frequencies of fusant formation varied depending upon the strains used and were 3.51$\times$10$^{-4}$ to 5.04$\times$10$^{-4}$ for the regenerated protoplasts. The strains capable of extensive starch hydrolysis produce only 10% to total fusants. The 4 strains were finally selected by the results of starch fermentation and genetic stability test. The DNA content and cell volume of the fusants were greater than those of the parental strains.

• Microbiology and Biotechnology Letters
• /
• v.16 no.6
• /
• pp.489-493
• /
• 1988

To obtain a new yeast strain that is able to efficiently produce ethanol from starch, the glucoamylase gene of Saccharomyces diastaticus was transformed into S. cerevisiae without a cloning vector. The competent cells of S. cerevisiae, induced by the treatment of Li$_2$SO$_4$, were transformed with the partial BamHI-digests of chromosomal DNA of S. diastaticus, and the transformants were selected by their abilities to utilize and ferment starch. The transformants, which appeared at a frequency of 8.5$\times$10$^{-7}$, were able to withstand up to 800 ppm of copper sulfate like the recipient and retained the phenotypic expression of the recipient with the exception of the acquisition of STA gene and MAL gene, as regards fermentation of carbohydrates. The enzymatic properties of glucoamylases produced by transformants were very similar to those produced by S. diastaticus as based on optimium pH and temperature.

• Microbiology and Biotechnology Letters
• /
• v.14 no.5
• /
• pp.359-363
• /
• 1986

S. diastaticus hydrolysised $\alpha$-1.4 linkage of the starch and was known fermenting yeast strain, but poorly hydrolized $\alpha$-1.6 linkage of the starch. To improve the starch fermentation ability of yeast, we tried that protoplast fusion between S. diastaticus and C. tropicalis and finally two starins of fusant (FPDC42, FPDC43) were obtained. C. tropicalis well hydrolysis both $\alpha$-1.4 and $\alpha$-1.6 linkanges in the starch. The protoplast of parental auxotrophic cells were fused in the presence of 10mM CaCl$_2$ and 35% of polyethylene glycol (M. W. 4,000). The fusion frequency was 10$^{-5}$ to 10$^{-6}$. Properties of the fusants(genetic stability, assimilation of carbon sources, random spore formation, copper resistance, NaCl tolerance, DNA content, cell size and growth rate) were investigated.

• Microbiology and Biotechnology Letters
• /
• v.14 no.5
• /
• pp.365-369
• /
• 1986

The activity of glucoamylase and pullulanase, properties of glucoamylase and ethanol productivities of fusants were studied. Glucoamylase and pullulanase activity of fusants were higher than parents. The optimal pH and temperature of glucoamylase of fusants were very similar to the those produced by S. diastaticus. In alcohol fermentation. fermenting ability and fermentation rate of fusants were higher and faster than either of its parental strain. The maximum of alcohol yield in 15% of liquefied potato starch was 7.8% (v/v)

• Microbiology and Biotechnology Letters
• /
• v.25 no.6
• /
• pp.537-545
• /
• 1997

The aim of the present research program was to isolate a strain of actinomycetes producing antifungal substance. Soil samples were collected from various sites in Korea and a number of actinomycetes were isolated from the soil samples by applying selective agar for actinomycetes. Among isolates, a strain (NA -52) producing antifungal substance against Pyricularia oryzae was selected. Chemotaxonomic and numerical identification were carried out for the isolate. Fifty taxonomic unit characters were tested and the data were analyzed numerically using TAXON program. The isolate was identified as a synonym of streptomyces diastaticus belong to cluster No. 19 (Streptomyces diastaticus). But it showed a low similarity to S. diastaticus in simple matching coefficients, hence it was considered as one new species in Streptomyces.

• Microbiology and Biotechnology Letters
• /
• v.22 no.6
• /
• pp.584-592
• /
• 1994

Several mutation procedures have been compared to obtain an ethanol-tolerant Saccha- romyces diastaticus strain secreting glucoamylase. These procedures include spontaneous mutation, EMS treatment, UV irradiation, and combination of EMS treatment and UV irradiation. All these methods were followed by adaptation of the yeast cells to gradually higher ethanol concentration. Among these procedures, the combined method of EMS treatment and UV irradiation gave the promising result, i.e. the ethanol tolerance of the yeast increased from 11.5%(v/v) to 14.0%(v/v). Respiratory deficient petite mutants of industrial and ethanol-tolerant yeast strains have been isola- ted and hybridized with haploid S. diastaticus strains. The resulting hybrids showed increased ethanol tolerance and starch-fermentability.